Surface Graphitized Mesoporous Carbon Surpasses the Conductivity-Porosity Trade-Off

In carbon engineering, a longstanding trade-off persists: chemical activation increases surface area but sacrifices conductivity, whereas graphitization enhances conductivity at the expense of porosity. In 2017, we introduced an electrochemical graphitization strategy using cathodic polarization in CaCl₂-NaCl molten salts to convert hard carbon into graphite. Here, we reveal that this graphitization process initiates at the surface and propagates inward, enabling the transformation of mesoporous hard carbon into surface-graphitized mesoporous carbon. Meanwhile, this phenomenon is an electrochemical activation process: short-term graphitization rearranges carbon atoms to increase surface area from 397 to 867 m²/g, without significant mass loss. Unlike chemical activation, which achieves similar surface area gains at the cost of >50% yield loss, our method maintains nearly 100% carbon yield while preserving mesoporosity. The resulting material delivers a 17-fold increase in electrical conductivity (26-450 S/cm). This scalable, energy-efficient approach resolves the long-standing graphitization-porosity dilemma, producing carbons with both high conductivity and large accessible surface area.